Heretofore, some buildings have employed a vibration isolating structure specially designed to minimize the effect of seismic vibrations in view of the properties of the seismic vibrations. One such vibration-isolated building incorporates a vibration isolator disposed between the ground and the building for minimizing forces transmitted to the building due to earthquakes.
According to such a vibration isolator, as shown in FIGS. 12A and 12B of the accompanying drawings, a building 301 is not fixed to a foundation 302, but a plurality of guiding apparatuses 303 for allowing the building 301 to move on the foundation 302 are disposed between the foundation 302 and the building 301. When seismic forces higher than a certain level are applied, the building 301 slides on the guiding apparatuses 303 to prevent the seismic forces from acting on the building 301.
There has been proposed a curved guiding apparatus or a three-dimensional guiding apparatus using steel rollers or balls as the guiding apparatus.
One such guiding apparatus comprises a guide member having a downwardly convex arcuate surface and steel rollers disposed between the guide member and a lower end of a building which is complementary in shape to the guide member (see Japanese laid-open patent publication No. 6-346627). Another guiding apparatus comprises a downwardly convex spherical guide member mounted on a foundation and steel balls disposed between the guide member and a lower end of a building which is complementary in shape to the guide member (see Japanese laid-open patent publication No. 5-24823).
With the vibration isolating structure employing the curved guiding apparatus or the three-dimensional guiding apparatus as described above, when vibrations such as seismic vibrations are not applied, the building is stably held in a steady position on the three-dimensional guiding apparatus or the like. When an earthquake occurs and the ground vibrates, vibrations are isolated between the ground and the building by the three-dimensional guiding apparatus or the like, and no substantial seismic vibrations are transmitted to the building.
After the vibrations of the ground have disappeared, the vibrations of the building attenuates with respect to the ground, and the building is stabilized in the steady position on the three-dimensional guiding apparatus.
The three-dimensional guiding apparatuses which have heretofore been proposed are designed and produced to suit individual buildings. There have not been available any three-dimensional guiding apparatus as component units of the vibration isolating structure having sufficient load-resistant performance and smooth operability for use as guiding apparatus used in vibration isolating structures of vibration-isolated buildings. There has been a demand for such three-dimensional guiding apparatus.
It is therefore an object of the present invention to provide a three-dimensional guiding apparatus which is capable of bearing large loads and can be used in a vibration isolating structure of a vibration-isolated building.